-LRB- CNN -RRB- -- When the sun went down , their voices did not .

Riot police on the street in Tehran on Monday .

`` Allah O Akbar ! '' the crowds on the tops of building chanted over and over .

Cell phone footage shows the nighttime scene in Tehran , Iran , which was sent to CNN 's iReport . As the camera pans with a jerk from building to building , protesters whistle and shout loudly while cars are heard honking in support .

The phrase , which means , `` God is great '' has become a rallying cry for protesting Iranians who have risked their lives and clashed with riot police because they believe the nation 's recent presidential election was rigged . Watch iReport video of the protest chorus

CNN spoke with the man who shot the footage . He did n't want to give his name . Doing so might jeopardize his impending escape from Iran and entry into Belgium , he said . He was reached by phone while driving in Tehran Sunday at 10 p.m. ET after he sent the video to iReport 's headquarters in Atlanta , Georgia . See iReporter 's cell phone photos taken Monday in Iran

He described seeing candles across the city which had been lit around 7 p.m. in Iran . Many were placed on rooftops in the memory of a woman known to the world as `` Neda . ''

A widely circulated video of the young woman shows her apparently in the middle of protests over the weekend with an older man , believed to be her father . It looks as though she is shot in the chest and drops to the ground . Blood runs from the side of her mouth as a few people , including the older man , press on her chest and shout her name . One pleads , `` Do not to be afraid . '' The camera closes in on her face as her eyes roll back and are still . She appears to die on camera .

Another shocking video sent to CNN 's iReport was also filmed from a rooftop , this time looking down at what seems to be an extremely violent scene on the roof of a shorter building . A group of men in black , members of the nation 's Basij militia , the iReporter says , appear to gang up on one man and beat him with batons . The footage shows him lying motionless as the men in black walk away .

Riot police and Basij militia tried to keep large crowds from congregating in Haft-e Tir Square and on Monday arrested at least eight people , witnesses said .

CNN 's international desk producers monitor official Web sites of the Iranian government . There has been no reaction to the violence posted on those sites , but the Iranian government has previously said that it does not approve of street protests .

Internet posts on Twitter and Facebook continue to be come from across the globe . Hundreds for Neda . `` More helicopters flying over Tehran today than any previous day '' someone from inside Iran tweeted Monday .

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Iranians chant their protest cry `` Allah O Akbar '' from rooftops

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iReporter says Iranians leaving candles on roofs in memory of woman killed

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Death of the woman , known as Neda , was captured on video and broadcast globally